1. Field of the Invention
This invention relates to a process for the production of alkyl benzene by hydrogenolysis of phenyl alkyl ketones and/or phenyl alkanols in which alkanols the alkanol moiety has at least two carbon atoms and the phenyl and hydroxyl groups are attached to the same carbon atom. These phenyl alkanols are hereinafter referred to as "starting alcohols".
2. The Prior Art
In certain processes for the epoxidation of ethylenically unsaturated compounds utilizing alpha-alkylphenyl hydroperoxides, 1-phenylalkanols and phenyl alkyl ketones are co-produced. Reconversion of these latter two compounds back to the hydroperoxide by hydrogenolyzing them back to alkylbenzene and oxidizing the alkylbenzene to the hydroperoxide improves the economics of the process by a recycling the by-products of the epoxidation reaction. Epoxy compounds are important intermediates for chemical manufacture and are also valuable and important materials of commerce.
Straus et al. in Ann., 439 (1924) at pages 298 and 299 demonstrates the production of ethylbenzene by passing hydrogen at atmospheric pressure at a temperature of 13.degree.C through a solution of methyl phenyl ketone in acetone containing finely divided palladium. Ethylbenzene is produced in a yield of 95%, but this method of hydrogenalysis took more than 11 hours. Golden et al. in U.S. Pat. No. 3,424,806 shows that the starting alcohols in the liquid phase in the presence of one or more metals of the platinum groups as catalyst at a temperature of at least 50.degree.C are hydrogenalyzed to the corresponding alkyl-aromatic hydrocarbons. He also states, however, that at temperatures above 120.degree.C hydrogenation of the aromatic ring takes place with consequent loss in yield of hydrogenolysis product.
Hata et al in Bull. Chem. Soc. Japan, 31 (1958), at pages 773 to 776 discloses the hydrogenolysis of methyl phenyl ketone at 203.degree.C to ethylbenzene in the vapor phase, using a nickel catalyst.
Khoobiar in British Pat. No. 1,116,378 discloses the hydrogenolysis of an aryl carbinol obtained in an oxidation process at 150.degree.-500.degree.C to the corresponding alkylaromatic hydrocarbon in the presence of a specific, but non-group VIII noble metal catalyst. Huneck in Naturwissenschaften, 48 (1961) at page 73 shows the hydrogenolysis of methyl phenyl ketone to ethyl benzene at 180.degree.C to 200.degree.C in the presence of a Cu-Cr catalyst.
Kindler et al., in Ann., 605 (1957) at pages 200 to 211 demonstrates the hydrogenolysis of methyl phenyl ketone and 1-phenylethanol to ethylbenzene In the presence of colloidal al. or platinum at ambient temperature.